I don't know if this girls giving me signs for something or wether I should stay away from her, could anyone help?

So I'm a 19 yo dude, I am in my final year at college ( UK), Im really inexperienced with girls so I'm fairly oblivious to more or less everything.

Context:
Me and this one girl who gets on my bus to college, we've had a previous altercation about a year ago and since coming back to college in September her and her friend have been messing with my head however it's more her friend doing this than the girl. This girls will join in but won't do too much beyond watching me.
This girls friend is a MASSIVE bitch, though.

I did confront the girl when she least expected it, about them watching me. she looked like she had shit herself and she denied everything.

On a certain day, this girl gets on the bus on her own and at the start of term she begun sitting far away and now likes to sit directly opposite me ( where I usually sit, in front of my mate. Quite odd for someone who I have been told is apparently uncomfortable with me...) And she will go sit there with no hesitation even when I'm already on the bus.
Most notably, I also have turned round to speak to my mate a few times and caught her eye but I know it wasn't me that initiated the eye contact, I've seen her eyeing me out by peripheral vision quite a few times, caught her looking at me through gaps in the bus seats occasionally and even one time where my mate could see her eyeing me before I even turned round.

She's been looking at me a lot when there really is no need to. I don't attract much attention from, well, anyone... So I really don't know why she would be eyeing me so much.

I spoke to my mate a few days ago about this, she thinks the girl likes me. She didn't explain how, said it's a "female thing" but I would assume its some type of intuition or inside knowledge of what females do when they like someone ( my mates a female and she's a lot older than me, got that life experience)

What the fuck is she playing at?
I don't know if this girls giving me signs for something or wether I should stay away from her, could anyone help?
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